Providing an exercise wheel by which animals can exercise without leaving a confined spaced is found within the prior art; however, none of the exercise wheels are configured to support a dog, particularly a large dog. For example, a cat exercise wheel is disclosed in U.S. Design Pat. No. D484,284, granted on Dec. 23, 2003, to Elmer Venson, et al. This cat exercise wheel is primarily intended for the animal to be walking on the interior surface or on the exterior circumference of the wheel and does not have the height or the width to permit a dog to walk within the interior surface of the wheel. Furthermore, this small exercise wheel is supported only on a central axial cantilevered bearing support that would not be adequate to support the weight of a dog.
U.S. Pat. No. 528,066, issued on Oct. 23, 1894, to Henry Ariens, teaches an exercise wheel that is intended for use by dogs. This exercise wheel is rotatably supported on an axially aligned bearing that enables the wheel to support the weight of a dog in a freestanding configuration although the support stand framework to position the axial bearing in an elevated location makes the entry to and the exit from the exercise wheel a dangerous and cumbersome task for the animal that is to utilize the exercise wheel. As a result, an exercise wheel of this configuration would not be commercially acceptable. Certainly, the Ariens exercise wheel would not be amenable to be mounted on a dog kennel to permit dogs housed therein to utilize the exercise wheel without leaving the confined kennel space.
The exercise wheel found in U.S. Pat. No. 1,794,951, granted on Mar. 3, 1931, to James Freer is configured to be used by small fur bearing animals, such as minks and foxes that are kept in captivity with the exercise wheel being mounted within the pen housing the animals. As with the Venson cat exercise wheel, this animal exercise wheel is supported on a cantilevered axial bearing and cannot withstand the weight of large animals. The Freer exercise wheel does resolve one problem associated with a freestanding exercise wheel, such as is found in the aforementioned Ariens patent, by mounting the exercise wheel on a cantilevered axial bearing support and closing the rear of the exercise wheel by a solid disk, the risk of injury to the animal by the shearing relationship between the support frame and the rotating wheel is eliminated. Because of the cantilevered mounting, however, the Freer exercise wheel is not readily mountable on the exterior surface of a dog kennel to permit a dog housed therein to gain access thereto for exercise without leaving the confinement of the dog kennel.
Similar to the Freer exercise wheel, a tread drum for animals, such as primates, having a cantilevered axial bearing support is disclosed in U.S. Pat. No. 4,088,094, issued on May 9, 1978, to Wayne Howard and assigned to NASA. This tread drum is intended to force animals utilizing the drum to exercise at a predetermined rate by incorporating a shocking apparatus that will stimulate the animal to move on the tread drum. As with the other known exercise wheels discussed above, the rotational support for the wheel itself is provided by an axial bearing extending in a cantilevered manner from a support frame. The tread drum disclosed in U.S. Pat. No. 5,125,361, granted to Scott Rowlands on Jun. 30, 1992, provides a unique four bearing support with rollers positioned along the outer circumference at the bottom portion of the tread drum that will adequately support the weight of a dog. The Rowlands exercise wheel is configured to be mounted on a base that can be easily disassembled from the exercise wheel. Without a support frame positioning an axial bearing support for the exercise wheel, the Rowlands tread drum has no pinch points that would present a danger to the animals using the exercise wheel. However, the Rowlands tread drum is not readily mountable to a dog kennel to allow dogs therein to obtain exercise without leaving the confinement of the dog kennel. Also, without a support frame, a dog could literally knock the Rowlands exercise wheel off of the roller bearings.
It would be desirable to provide an exercise wheel that can be used in a freestanding configuration or deployed on the exterior surface of a dog kennel to allow a dog housed within the kennel to gain access to the exercise wheel without leaving the confinement provided by the dog kennel.